Vibration reduction apparatus for power tool and power tool incorporating such apparatus

Abstract

A power hammer has a handle mounted to a housing and capable of limited movement relative thereto. A hollow axle is attached to the housing and is rotatable between a first and second position and is biased towards the first position by a torsional spring which extends within the axle. Rotation of the axle causes rotation of arms connected thereto. Connectors are slidably mounted within guides and are respectively connected at one end to each of the arms and at the other end to the handle. Vibrations in the housing cause movement of one end of the handle, which causes movement of the associated connector and arm. Movement of the one arm causes rotation of the axle, which therefore causes movement of the other arm and connector, and the other end of the handle. Thus, the movement of one end of the handle is coupled to the other end.

1. A handle assembly for a power tool, the assembly comprising:
 a handle adapted to be held by a user of the power tool and mounted to a housing of the power tool such that the handle is capable of movement relative to the housing; 
 an axle connected to the housing and rotatable relative to the housing between a first position and a second position, said axle including a hollow portion; 
 a torsional biasing element for urging said axle towards said first position, said torsional biasing element at least partially located in said hollow portion of said axle; and 
 an arm connected to said handle and adapted to pivot with said axle, wherein movement of said handle relative to said housing along at least one axis causes rotation of said axle relative to the housing. 
 
   
   
     2. An assembly according to  claim 1 , further comprising a connector connected between said handle and said arm for converting rotational movement of the arm into substantially linear movement of said handle. 
   
   
     3. An assembly according to  claim 2 , further comprising a guide connected to the housing and the connector is slidably mounted in the guide. 
   
   
     4. An assembly according to  claim 1 , wherein the axis of rotation of the axle is substantially parallel to a major dimension of the handle. 
   
   
     5. An assembly according to  claim 2 , wherein said connector is a first connector attached adjacent a first end of said handle, and the assembly further comprises a second connector attached adjacent a second end of said handle. 
   
   
     6. An assembly according to  claim 1 , further comprising adjustment means for adjusting the biasing force of said biasing element. 
   
   
     7. An assembly according to  claim 6 , wherein said adjustment means is adapted to adjust said biasing force in said biasing element by moving and fixing a portion of said biasing element relative to said housing. 
   
   
     8. An assembly according to  claim 6 , wherein said adjustment means comprises at least one cam adapted to rotate about a respective first axis to move and fix a portion of said biasing element relative to said housing. 
   
   
     9. An assembly according to  claim 8 , wherein rotation of said cam about the first axis causes movement of a portion of said biasing element in a direction substantially parallel to the axis of rotation of the cam. 
   
   
     10. A power tool comprising:
 a housing; 
 a motor in the housing for actuating a working member of the tool; and 
 a handle assembly including:
 a handle adapted to be held by a user of the power tool and mounted to a housing of the power tool such that the handle is capable of movement relative to the housing; 
 an axle connected to the housing and rotatable relative to the housing between a first position and a second position, said axle including a hollow portion; 
 a torsional biasing element for urging said axle towards said first position, said torsional biasing element at least partially located in said hollow portion of said axle; and 
 an arm connected to said handle and adapted to pivot with said axle, wherein movement of said handle relative to said housing along at least one axis causes rotation of said axle relative to the housing. 
 
 
   
   
     11. A power tool according to  claim 10 , further comprising a connector connected between said handle and said arm for converting rotational movement of the arm into substantially linear movement of said handle. 
   
   
     12. A power tool according to  claim 10 , further comprising a guide connected to the housing and the connector is slidably mounted in the guide. 
   
   
     13. A power tool according to  claim 10 , wherein the axis of rotation of the axle is substantially parallel to a major dimension of the handle. 
   
   
     14. A power tool according to  claim 11 , wherein said connector is a first connector attached adjacent a first end of said handle, and the assembly further comprises a second connector attached adjacent a second end of said handle. 
   
   
     15. A power tool according to  claim 10 , further comprising adjustment means for adjusting the biasing force of said biasing element. 
   
   
     16. A power tool according to  claim 15 , wherein said adjustment means comprises at least one cam adapted to rotate about a respective first axis to move and fix a portion of said biasing element relative to said housing.